The invention relates to a medical instrument, in particular a uretero-renoscope, with a proximal head part and with an elongate thin shaft for introduction into elongate hollow organs, in particular into a ureter.
Medical instruments of this kind are known, for example, from the Applicant's catalogue “Urologie”, 7th edition, 1/2003, section 10 “Uretero-Renoskope”.
For their application in urology, instruments of this kind are intended to be able to be inserted into hollow organs in the form of ureters. For this purpose, they have an extremely long and thin shaft, for example with a length in the region of up to 50 cm and with a diameter of 2 to 5 mm.
Several channels are present in the shaft itself. One channel serves as instrument channel to allow an instrument, for example an ultrasound probe, to be conveyed through the shaft, for example in order to crush a stone located in a ureter.
Moreover, in order to monitor these procedures, there is a further channel for an optical system consisting of light guides and image guides, and at least one suction and irrigation channel. In some designs, the suction channel and irrigation channel are separate, so that there are four channels in total. These channels are packed as closely as possible together in the shafts, said shafts accordingly having oval, rounded or elliptic cross sections, or cross sections flattened on side, as is evident from the catalogue mentioned above.
A common feature of all designs is that the instrument channel is arranged laterally.
In practical use, it has now been found that there is a risk that instruments pushed out distally via the instrument channel may damage the wall of the ureter. Since these instruments are extremely thin, they have a certain flexibility. The risk of damage arises upon lateral deflection and penetration into the wall of the ureter, especially in the case of an instrument pushed out past the distal tip of the shaft.
It is therefore an object of the present invention to rectify this situation and provide an instrument which largely avoids such damage.